Various devices have been used to store glass slides, such as microscope and patient test slides. One known storage receptacle is a slide cassette. A cassette typically includes a pair of trays and or retaining members or fingers that extend from the cassette and below a slot. A slide fits into a slot and onto a tray. Each slot receives a single slide. The dimensions of a slot are typically larger than the dimensions of a slide so that the slide can be easily inserted into and removed from the slot.
Automated or semi-automated imaging systems use robotic actuators or other devices to remove a slide from the cassette, process the slide or specimen, and return the slide into the cassette. For example, one device may acquire a slide from a cassette and position it beneath a microscope or other device so a cytotechnologist can analyze the sample for cancer and other medical conditions. More specifically, the imaging system grasps the slide, lifts it above the retaining members of the trays, removes the slide from the trays and the slot, and positions the slide beneath the microscope. The imaging system re-inserts the slide into the cassette after the analysis is completed.
The manner in which imaging systems and other devices check the orientation of slides in a slide cassette can be improved. Ideally, all of the slides are properly arranged flat on the trays inside the cassette and in a similar manner. However, as a result of human or machine errors, slides may be improperly loaded into a cassette. For example, a slide may not rest flat on the trays. Instead, the slide may only partially clear one of the trays and come to rest at an angle. Further, the slide can be inserted upside down so that surface with a specimen sample is facing downward, whereas other slides may have their specimen samples facing upward. Further, slides can be twisted around. In other words, the slide may be inadvertently rotated 180 degrees. This may present a problem when, for example, a bar code or other data is present on one end of a slide.
Slides that are improperly positioned may also be broken by equipment that is programmed to select slides since the equipment is typically configured to select or re-insert a slide that is oriented in a particular manner. Thus, equipment errors and broken slides can result from misplaced slides. These errors can also result in system downtime while a cytotechnologist or technician is forced to examine the cassette and rearrange misplaced slides or retrieve broken slides.
Accordingly, there exists a need for a system and method that checks or provides an indication of the arrangement or orientation of slides in a cassette to ensure that all of the slides are properly arranged. Such a system and method would improve the performance of processing equipment, safety, throughput and operator convenience.